title: Force decay of elastomeric chains - a mechanical design and product comparison study.
abstract: OBJECTIVE
  To evaluate the percentage force decay of elastomeric chain products utilizing three different design mechanisms simulating canine retraction; and to evaluate the percentage force decay of elastomeric chain products from four different companies.
  
  
  METHODS
  In vitro, laboratory study.
  
  
  METHODS
  LSUHSC Dental School, New Orleans, LA, USA.
  
  
  METHODS
  Closed (non-spaced), grey elastomeric chains from four companies were selected for the study. Three acrylic resin jigs were constructed to provide a framework for three simulated space closure mechanisms. The 6-5-3, the chain loop, and the 6-3 were the configuration mechanisms used in the study.
  
  
  METHODS
  An electronic force gauge was used to measure the percentage force decay associated with each elastomeric chain over 28 days at preselected times.
  
  
  RESULTS
  There was a significant difference in the mean percentage force decay for the three different mechanisms (P < 0·001). For all four companies, the 6-3 mechanical design had the smallest mean percentage force decay. There was a significant difference in the mean percentage force decay for the different companies (P < 0·001). For all three mechanisms, Ormco had the smallest percentage force decay while Unitek had the highest percentage force decay.
  
  
  CONCLUSIONS
  The significant difference in the mean percentage force decay for the different mechanisms suggests that the 6-3 design is a more efficient means of closing extraction spaces utilizing elastomeric chains.
authors.affiliation: LSU Health Sciences Center, New Orleans, Louisiana, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Balhoff
authors.forename: Matthew
authors.initials: M
authors.lastname: Shuldberg
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Hagan
authors.forename: Richard W
authors.initials: RW
authors.lastname: Ballard
authors.forename: Paul C
authors.initials: PC
authors.lastname: Armbruster
mesh_terms: D003481:Cuspid; D003764:Dental Materials / Q000737:chemistry*; D020724:Elastomers / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D055595:Mechanical Phenomena; D008953:Models, Anatomic; D016382:Orthodontic Appliance Design; D009967:Orthodontic Appliances; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D013314:Stress, Mechanical; D013997:Time Factors; D014087:Tooth Movement Techniques / Q000295:instrumentation
chemical_list: D003764:Dental Materials; D020724:Elastomers